The present invention relates to a manufacturing method for a suspension for a magnetic head.
As shown in FIG. 9, in the suspension 10 for the magnetic head, a magnetic head element (slider) 12 is mounted on the end side of a load beam 11 made of a spring material such as stainless steel and a wiring pattern 13 electrically connected to the magnetic head element 12 is formed on the load beam 11. The load beam 11 is fixed to an arm part 18 of an actuator 17 through a spacer 14 at one end side thereof to perform a seeking movement (see FIG. 10). FIG. 10 shows a magnetic disk device. Reference numeral 19 designates a spindle and 20 designates a magnetic disk. The wiring pattern 13 is formed on an insulating resin layer 15 made of a polyimide resin, an epoxy resin, an acrylic resin, etc. with a prescribed width on the load beam 11 as shown in FIG. 11. The wiring pattern 13 is further covered with a protective layer 16 made of a photo-sensitive resin, a polyimide resin, an epoxy resin, an acrylic resin, a resist, etc. Externally connecting terminal parts 13a of the wiring pattern 13 are exposed. Further, the parts of the terminal parts of the wiring pattern 13 connected to the magnetic head element 12 are also exposed by forming an opening part (not shown in the drawings) on the protective layer 16.
As shown in FIG. 9, a slider mounting part 22 on which the magnetic head element (slider) 12 is mounted is supported by a traverse beam 24 of a beam shaped support part (generally called a gimbals part) 25 formed substantially in an H-shape by two longitudinal beams 23 and one traverse beam 24. The slider 12 is fixed to the slider mounting part 22 by an adhesive agent. The slider 12 is urged toward a medium side by the resilient force of the load beam 11. When the medium is rotated at high speed upon reading and writing data, the slider slightly floats at a position where a wind force from the medium balances the resilient force of the load beam 11. Accordingly, the load beam 11 needs a part having a resiliency and a part having rigidity capable of preventing a deformation due to torsion. The resiliency is obtained by a part 11a called an R bend. The rigidity is obtained by forming, for instance, a bent and folded part 11b in the load beam 11. The gimbals part 25 is not limited to the above-described structure, however, requires a prescribed degree of freedom.
Nowadays, as the medium has a high density, the magnetic head element (slider) 12 is miniaturized and the suspension 10 for supporting the slider 12 is also apt to be progressively miniaturized. Accordingly, as a resilient metallic material that forms the load beam 11, for instance, a thin stainless steel material having the thickness of about 25 μm or the like has been used. The adjustment of floating characteristics (resilient pressure, rigidity) reaches a limit depending on the above-described bending work. On the other hand, an impedance of the suspension 10 side to an external connecting part thereof needs to be adjusted. To adjust the impedance to the external connecting side, the thickness of the insulating resin layer 15 on the load beam 11 needs to be increased.
As described above, the thickness of the insulating resin layer 15 is increased so that the rigidity is increased, and the resilient pressure or the torsion can be prevented conveniently in this respect. However, the rigidity of the gimbals part 25 in the vicinity of the slider mounting part 22 conversely becomes too high, so that the degree of freedom is undesirably the more lowered. Thus, recently, the thickness of the insulating resin layer 15 near the slider mounting part 22 is smaller than that of other parts to ensure the degree of freedom of the gimbals part 25.
To make the insulating resin layer 15 in the vicinity of the slider mounting part 22 thinner than other parts, such a manufacturing method as described below has been usually employed. That is, as shown in FIG. 12, a first insulating resin layer 26 is firstly applied to the load beam 11. Then, a photo-resist layer (not shown) is formed on the first insulating resin layer 26, exposed and developed to form a photo-mask 27 (see FIG. 13). An etching process is carried out by using this photo-mask 27 as a mask to form a prescribed pattern on the first insulating layer 26 (see FIG. 14). After the photo-mask 27 is removed, the first insulating resin layer 26 is coated and applied with a second insulating resin layer 28, as shown in FIG. 15. Then, a photo-resist layer (not shown) is formed on the second insulating resin layer 28, exposed and developed to form a photo-mask 29 (see FIG. 16). An etching process is carried out by using the photo-mask 29 as a mask to leave the second insulating resin layer 28 (see Fig. 17) on the first insulating resin layer 26 in a part from which the gimbals part 25 is removed. In such a way, since only the first thin insulating resin layer 26 is formed on the gimbals part 25, the rigidity is not increased too much to ensure a necessary degree of freedom.
However, the above-described related art has such a problem as described below. That is, two film forming processes of forming the first insulating resin layer 26 and the second insulating resin layer 28 are necessary so that the number of processes is undesirably increased and a cost is inconveniently increased.